Linear-accelerator X-ray output: a multicentre chamber-based intercomparison study in Australia and New Zealand

  • M. A. Ebert
  • S. J. Howlett
  • K. Harrison
  • D. Cornes
  • C. S. Hamilton
  • J. D. Denham
Scientific Papers


This paper describes the process and results of a survey of linear accelerator outputs as part of an Australasian Level III Dosimetry Intercomparison. This study involved the measurement of accelerator output under reference conditions (‘Level I’) with a small-volume ionisation chamber in water for 47 beams at 36 radiotherapy centres using the IAEA TRS 398 dose-to-water protocol. The mean ratio of measured to locally-determined accelerator output was 1.003±0.009 (1 standard deviation) with a range from 0.981 to 1.024. No correlation could be found between output ratio and accelerator type or local output calibration protocol. The small-volume chamber used satisfied most requirements for the study though showed some variation in sensitivity via repeated cross-calibration with a chamber calibrated at a primary standards laboratory.

Key words

TRS 398 radiotherapy audit dosimetry intercomparison 


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Copyright information

© Australasian College of Physical Scientists and Engineers in Medicine 2008

Authors and Affiliations

  • M. A. Ebert
    • 7
    • 1
  • S. J. Howlett
    • 2
  • K. Harrison
    • 3
  • D. Cornes
    • 4
  • C. S. Hamilton
    • 5
  • J. D. Denham
    • 3
    • 6
  1. 1.School of PhysicsUniversity of Western AustraliaPerthAustralia
  2. 2.Australasian College of Physical Scientists and Engineers in MedicineMelbourneAustralia
  3. 3.Department of Radiation OncologyCalvary Mater NewcastleNewcastleAustralia
  4. 4.Trans-Tasman Radiation Oncology GroupCalvary Mater NewcastleNewcastleAustralia
  5. 5.Heidelberg Repatriation HospitalVictoriaAustralia
  6. 6.School of Medicine and Population HealthUniversity of NewcastleNewcastleAustralia
  7. 7.Department of Radiation OncologySir Charles Gairdner HospitalNedlandsAustralia

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